NOMOS. 



43 



by the formation of a second molecule of chloride of 

 zinc. This is formed, as before, by the union of 

 the positive element (chlorine) of the remaining 

 hydrochloric acid molecule with the negative element 

 of the remaining zinc molecule, and consequently, 

 the hydrochloric acid and zinc molecule are both 

 decomposed. The negative element of the hydro- 

 chloric acid (hydrogen) is thus set at liberty, and so 

 is the positive element of the zinc molecule, and the 

 result is a double train of decompositions and recom- 

 binations, such as that we have already described. 

 Thus : 



Fig. 8. 



The next change is also a repetition of that which 

 has been already described. This change begins by 

 the escape of the hydrogen which for a moment 

 tended to unite with the positive element of the 

 contiguous platinum molecule, and by the precipi- 

 tation of the molecule of chloride of zinc ; and it 



